The Bears announced the move on Friday, just four days after Fox and the Denver Broncos parted ways.

Fox was widely seen as a strong candidate to replace the fired Marc Trestman once he left the Broncos on Monday, given his record and his ties to consultant Ernie Accorsi and new general manager Ryan Pace.

Fox was the defensive coordinator for the New York Giants from 1997 to 2001 when Accorsi was the GM. Saints coach Sean Payton was the offensive coordinator for part of that time. Pace was hired out of New Orleans' front office.

Fox won the AFC West all four seasons in Denver and reached the Super Bowl last year.